Download What is energy?

What is energy?
What is energy?
What is energy?
What is energy?
Energy is a property of objects, transferable among them
via fundamental interactions, which can be converted into
different forms but not created or destroyed.
What is energy?
Energy is a property of objects, transferable among them
via fundamental interactions, which can be converted into
different forms but not created or destroyed.
Example/
PE = Potential Energy = Energy of Position
Gravitational PE
Spring PE
Gravitational Potential Energy =
= mgh = (mass)(gravity)(height)
Gravitational Potential Energy =
= mgh = (mass)(gravity)(height)
All energy is measured using the joule (in SI)
Gravitational Potential Energy =
= mgh = (mass)(gravity)(height)
All energy is measured using the joule (in SI)
How much is 1 joule?
Gravitational Potential Energy =
= mgh = (mass)(gravity)(height)
All energy is measured using the joule (in SI)
How much is 1 joule?
1 joule = mgh = (0.1 kg)(~10 m/s2)(1 m)
0.1 kg = 3.5 oz
Gravitational Potential Energy =
= mgh = (mass)(gravity)(height)
All energy is measured using the joule (in SI)
How much is 1 joule?
1 joule = mgh = (0.1 kg)(~10 m/s2)(1 m)
0.1 kg = 3.5 oz
Gravitational Potential Energy =
= mgh = (mass)(gravity)(height)
Where do you measure h from?
Expanding Universe: Sum of radiation&mass (positive) and
gravitational potential energy (negative) = zero (?)
Forms of Energy:
KE = Kinetic Energy (motion) =
= ½ mv2 = ½ (mass)(velocity)2
Forms of Energy:
KE = Kinetic Energy (motion)
PE = Potential Energy (position)
ME = Mechanical Energy = KE + PE = ½ mv2 + mgΔh
Forms of Energy:
KE = Kinetic Energy (motion)
PE = Potential Energy (position)
ME = Mechanical Energy = KE + PE = ½ mv2 + mgΔh
What happens, eventually?
Forms of Energy:
KE = Kinetic Energy (motion)
PE = Potential Energy (position)
ME = Mechanical Energy = KE + PE = ½ mv2 + mgΔh
What happens when you bounce a ball?
During every bounce, some amount of energy is lost to heat,
usually by internal or external friction
High-speed golf ball impact:
Baseball deforming during impact:
Baseball deforming during impact:
Other Forms of Energy:
Thermal Energy
Chemical Energy
Nuclear Energy (Mass)
Electrical Energy
Physical Wave Energy (sound, water waves, seismic waves)
Radiant Energy (electromagnetic radiation; “light”)
Thermal energy is a measure of the total kinetic energy of
the particles of a substance.
Thermal energy is a measure of the total kinetic energy of
the particles of a substance.
Temperature is a measure of the average kinetic energy of
the particles of a substance.
Thermal
energy:
More
Less
Temperature:
Same
Same
Heat is the transfer of thermal energy
Heat is the transfer of thermal energy
Work is the transfer of mechanical energy:
W = F d = (Force x Distance)
F = ma = (Mass x Acceleration)
Law of conservation of energy: During a conversion from one
form of energy into another, the total amount of energy doesn’t
change
During every energy conversion, some amount of energy is lost
to heat, usually by internal or external friction
Law of conservation of energy: During a conversion from one
form of energy into another, the total amount of energy doesn’t
change
Other Forms of Energy:
Thermal Energy
Chemical Energy
Nuclear Energy (Mass)
Electrical Energy
Physical Wave Energy (sound, water waves, seismic waves)
Radiant Energy (electromagnetic radiation; “light” waves)
World Energy Consumption, by Source (2013)
World Energy Consumption, by Source (2013)
[EIA = Energy Information Administration]
World Energy Consumption, by Source
(1 exajoule = 1 EJ = 1 quintillion joules = 1018 j)
(1 Quad = Quadrillion British thermal units =
= 1.055 exajoules = 1.055 EJ)
Where in the world is the fastest growth in energy
production?
How much of U.S. energy is imported?
Is U.S. per capita energy use increasing or decreasing?
Historical World Energy Production
(Gboe = billion barrels of oil equivalent)
What is most U.S. energy used for?
What are the energy sources for transportation?
What is the efficiency of U.S. cars and trucks?
What are the major energy sources produced in the U.S.?
Where does your electricity come from?